The field of invention generally relates to ski boot to ski binding interface, and more particularly, to a ski boot to binding interface, where the toe piece is a releasable tech style binding and the heel retention is accomplished using a rear mounted flexible cable style binding.
The general activity of skiing comprises many subsets of activities, including, but not limited to alpine touring, telemark, cross-country, and downhill. Each subset generally corresponds to a unique system of specialized equipment. For example, the boot and binding systems used for telemark skiing differ significantly from those used for downhill skiing. A skiing system may include standard types of bindings, boots and skis. Each type of skiing corresponds to unique characteristics of a binding to achieve optimal performance for that type of skiing. In addition, particular terrain, distance traveled and skier preference may require an even more specific set of performance characteristics. Boots and bindings must be compatible with each other in order to interface effectively.
Telemark skiing requires that a user be able to articulate their foot, bending the metatarsal phalangeal joint and allowing the user's heel to rotate away or rise in respect to the top surface of the ski. Most conventional telemark boot binding interface systems utilize an extended sole at the front of the boot called a “duckbill” and metal clamp or bail to couple the boot to the ski. The rotational freedom of the user's heel is limited by the flexibility of the boot and binding coupling. This system requires that the duckbill and toe region of the boot be sufficiently rigid to prevent undesired torsion of the duckbill and to allow the user to control the trailing ski while executing a telemark turn. The required rigidity necessitates relatively heavy material for both the duckbill and toe portion of the boot. This duckbill boot binding interface creates a toe biased pivot that is difficult to eliminate without over compensating by significantly increasing the rigidity and weight of both the boot and binding.
It is highly desirable while ascending steep terrain to freely rotate the user's foot vertically with a full range of motion. A freely rotating pivot connection near the user's toe allows the skier to make an efficient, resistance free, stride. A rigid duckbill style boot and conventional telemark bindings resist upward rotating movement of the foot while ascending, significantly increasing the effort required to ascend. Some current telemark bindings accomplish a free range of motion by adding a pivot or hinged plate to the front of the telemark binding. However, this arrangement can increase the binding weight and creates an unpleasant noise when the hinge and associated plate contacts the ski top sheet. Additionally, this arrangement also often has a limited range of motion due to the metal clamp impeding forward travel of the binding.
Traditional telemark bindings create a fixed attachment between the boot duckbill and a rigid binding bail. This arrangement does not allow the skier to be separated from the ski unless the user manually releases the bail. If a skier is caught in an avalanche, a fixed ski can act as an anchor, preventing them from rising to the surface of the snow and increasing their chance of a fatal burial. Additionally, an attached ski can generate significant torsional stress on a skier's lower leg in the event of a violent crash, possibly causing fractures and knee injuries.
Tech style bindings, such as the Dynafit® TLT, have been in production since the early 1990's and have provided an alternative to traditional telemark bindings for backcountry skiing. The tech style front binding toe piece uses two spring loaded pins that fit into corresponding holes or sockets in the sides of the ski boot toe. The pins allow the boot to freely rotate from a planted or relaxed position on the ski, to a position where the sole of the boot is flexed or past perpendicular to the ski. This full rotational movement allows the skier to freely slide the ski when gliding or to lift the ski when ascending a slope. The tech style front binding also provides the increased safety of a “rough” (non-calibrated and non-adjustable release) release in the event of a crash, potentially protecting the user's leg and knee. Some tech style toe connections compatible with the telemark tech system offer a calibrated, adjustable release. Tech style toe piece bindings are designed to be used in correlation with a rear binding where a user's heel is locked in a fixed position attached to the ski when descending. This fixed position forces the user to descend using parallel turns, typically associated with downhill skiing, or alpine touring. A signature trait of the telemark turn is the user flexes both knees with the majority of their weight on the downhill ski; the uphill ski drops behind in an offset position, forcing the user's heel to rise away from the trailing ski. A proper telemark ski turn cannot be executed when using skis equipped with a fixed heel, such as, tech style bindings, as commonly known in the art.
Therefore, there is a need in the industry for a boot binding interface system that has a fully rotating front binding, minimizes weight, optimizes telemark skiing performance and is releasable.